Every once in awhile you see something in the “it’s worse than we thought” meme that deserves some clarification for those that want to look at all the data, rather than those who want to push gloom and doom. A recent tweet by Bill McKibben thoughtlessly retweeting a statement by the Master of Disaster, Weather Underground’s Dr. Jeff Masters, got me digging to see just how true it was. Here’s the tweet:
Dear Ms. Andrea Angulo, the answer is: we’ve done nothing wrong, because this isn’t the worst USA drought by any measure nor did we cause it (it was a natural weather oscillation the NAO, and stop following weepy Bill and look for yourself rather than being a flock member).
Jeff Masters’ claim doesn’t hold up when you look at all the data, and it is a claim of his own invention that not even NOAA said anything about. Let’s look at Masters claim:
But Masters didn’t really bother to visualize all the drought data he cited, preferring instead to simply make a pronouncement, which is then unthinkingly parroted by folks like McKibben. I took the CONUS drought area data Masters linked to in the article from:
And plotted it, noting the years Masters referred to:
Not so scary now, is it? But it becomes even less scary when you don’t cherry pick the data you want, but instead look at all the drought data available to you. Quite frankly, since Masters holds a PhD. in meteorology, you’d think he’d know to look at the most widely accepted metric, the Palmer Drought Severity index (PDSI) also available from NOAA.
Negative values are dry (in yellow) positive values are wet (in green) Source: http://www.ncdc.noaa.gov/temp-and-precip/time-series/index.php?parameter=pdsi&month=11&year=2012&filter=ytd&state=110&div=0
(Note: the 2012 value is a slim yellow line to -4 on the right axis)
Using the Year-to-Date average Palmer Drought Severity Index, 2012 is just another blip compared to others in the last century, and hardly rates a mention. But that doesn’t fit Masters and McKibben’s ongoing gloom and doom meme, so they don’t want to look at it or show it to their followers. But wait, there’s more.
From Sheffield et al 2012, plotting the Palmer Drought Severity Index globally over the past 60 years they show little change in drought severity, and certainly no response to “global warming”.
a, PDSI_Th (blue line) and PDSI_PM (red line). b, Area in drought (PDSI <−3.0) for the PDSI_Th (blue line) and PDSI_PM (red line). The shading represents the range derived from uncertainties in precipitation.
From their abstract:
Here we show that the previously reported increase in global drought is overestimated because the PDSI uses a simplified model of potential evaporation that responds only to changes in temperature and thus responds incorrectly to global warming in recent decades. More realistic calculations, based on the underlying physical principles that take into account changes in available energy, humidity and wind speed, suggest that there has been little change in drought over the past 60 years.
So even the PDSI may have errors, making it overestimate drought severity, and it isn’t just one paper saying this. Martin Hoerling of NOAA says:
Hoerling et al. in Journal of Climate: Is a Transition to Semi-Permanent Drought Conditions Imminent in the U.S. Great Plains?
“We conclude that projections of acute and chronic PDSI decline in the 21st Century are likely an exaggerated indicator for future Great Plains drought severity.”
Climatologist Dr. Pat Michaels, in his previous WUWT opinion piece, noted that NASA GISS Dr. James Hansen is making a claim that global temperatures are driving U.S drought, and did a scatterplot to gauge correlation between Hansen’s own GISS temperature data (GISTEMP) and the U.S. Palmer Drought Severity Index with annual data through 2011:
Annual PDSI -vs- Annual Global GISTEMP – Source: Dr. Pat Michaels
There’s no correlation: zero, zip, nada. If there were, you’d see the dots align along a diagonal line, there’s not even a hint of that. Of course doom and gloom proponents like Masters and McKibben might say “… but, but, but, 2012 was a terrible drought”. Yes, it was, it is, but we’ve seen worse in the past.
One final note, about the real worry of drought in the USA; effects on the food supply.
Note how 2012 compares to drought years of 1934, 1936, and 1988. It is certainly no outlier.
And, the trend for yield continues upward, with 2012 not even coming close to some of the worst years for production.
Agricultural science trumps a drought year. That’s a hockey stick we can all believe in.
Call me a “doubting Thomas” as to overwrought claims by Masters and McKibben, but the fact is that the 2012 drought isn’t as bad as they would have you believe and won’t show you these other data because they don’t fit their business model.
Regarding corn, recall what Bill McKibben once
Those damned shriveled ears of corn. I’ve done everything I can think of, and millions of people around the world have joined us at 350.org in the most international campaign there ever was.
Everything that is, but look at the data.